diff --git a/docs/asset-engine/CATALOG-CONTRACT.md b/docs/asset-engine/CATALOG-CONTRACT.md
index ca31fb5..52d74a5 100644
--- a/docs/asset-engine/CATALOG-CONTRACT.md
+++ b/docs/asset-engine/CATALOG-CONTRACT.md
@@ -144,7 +144,7 @@ reference implementation of this pattern; copy the script shape from
 
 | Consumer                                    | Vendored at                          | Pin policy        |
 |---------------------------------------------|--------------------------------------|-------------------|
-| `asset_engine` (FastAPI/HTMX UI; ~/development/asset_engine/) | `data/services.yaml` + `data/services.yaml.lock` | catalog_version=1 |
+| `asset_engine` (FastAPI/HTMX UI; ~/development/asset_engine/) | `data/services.yaml` + `data/services.yaml.lock` | catalog_version=2 |
 
 When you add a consumer, add a row here in the same PR that lands
 the consumer. This list is what we audit when planning a
diff --git a/docs/asset-engine/services.schema.json b/docs/asset-engine/services.schema.json
index ff63527..5949afe 100644
--- a/docs/asset-engine/services.schema.json
+++ b/docs/asset-engine/services.schema.json
@@ -85,6 +85,12 @@
           "title": "Optional",
           "type": "boolean"
         },
+        "togglable": {
+          "default": false,
+          "description": "When true, the consumer renders this field with an OFF-by-default enable switch; while off the control is disabled (excluded from submission) AND the field's default is NOT injected, so it is genuinely not sent until the user opts in. Requires optional=true. Used to keep advanced override fields (e.g. inline clone references) from silently overriding primary controls.",
+          "title": "Togglable",
+          "type": "boolean"
+        },
         "default": {
           "default": null,
           "title": "Default"
diff --git a/docs/asset-engine/services.yaml b/docs/asset-engine/services.yaml
index c4e7459..ed4d811 100644
--- a/docs/asset-engine/services.yaml
+++ b/docs/asset-engine/services.yaml
@@ -16,7 +16,7 @@
 # specific service's parameter shape changes. Both let downstream
 # consumers detect drift.
 
-catalog_version: 1
+catalog_version: 2
 
 services:
   - id: kokoro
@@ -763,6 +763,7 @@ services:
         label: Custom clone (inline base64)
         section: advanced
         optional: true
+        togglable: true
         description: >
           Power-use: zero-shot clone from a reference NOT in the staged library
           — array of {audio: <base64-encoded WAV bytes>, text: "transcript"}.